Re: [avr-gcc-list] Parm to application

[Georg-Johann Lay]

Parthasaradhi Nayani schrieb:
> Hello all, I have a boot loader and an application on a Mega168.
> As boot loader and application are two different entities, is there
> any way the boot loader can pass a parameter to application code?
> Would like something like main (int argc, char *argv[])

Reserve a piece of RAM that does not depend on how the application
is compiled, for example at the start of .data (bump .data to a later
location) or at the top of the stack (initialize SP to RAMEND-offset).

In the boot loader, write the data to that reserved space.

In the application, write a startup function for section .init8,
preferably as naked assembler, that reads that data and prepares
it according to the ABI, i.e. pass argc in r24/25 etc.

Then call main (int, char*[]) and receive the arguments.

It should also be okay to call main from .init8 by hand if
you prefer C, e.g.

  main (argc, argv);
  _exit (0);

or

  main (argc, argv, env);
  _exit (0);


Johann